The invention relates generally to electrical connectors and, more particularly, to a connector assembly that mechanically and electrically connects circuit boards.
Known mezzanine connectors mechanically and electrically connect circuit boards. With some known mezzanine connectors, the mezzanine connectors may be mounted to one circuit board and a mating connector is mounted to another circuit board. The mezzanine connector and the mating connector mate with one another to mechanically and electrically interconnect the circuit boards. Contacts in the mezzanine connector mate with one of the circuit boards and with contacts in the mating connector to provide electrical connections between the circuit boards.
Some known mezzanine connectors communicate differential signals at relatively high data rates between the circuit boards. For example, the connectors may include at least two signal contacts that communicate the differential signals and several ground contacts that are electrically coupled to a ground reference. The ground contacts may shield the signal contacts from electromagnetic interference to improve the integrity of the differential signals communicated via the signal contacts.
In order to reduce electrical impedance characteristics of the signal contacts, the signal and ground contacts may be located closer together in the mezzanine connector. For example, the ground contacts may be located in the mezzanine connector in positions that are relatively close to the signal contacts to increase the amount of electromagnetic interference that is shielded from the signal contacts. Due to tooling and manufacturing tolerances involved in the manufacture of the mezzanine connectors, however, the signal and ground contacts may not be able to be located closer than a minimum distance. For example, the tools involved in cutting openings in the mezzanine connector in which the signal and ground contacts are held may be limited in how closely the signal contact openings can be positioned to the ground contact openings. Consequently, some known connectors include solid masses or blocks of dielectric material that extend throughout the connectors. The ground and signal contacts are held in the same block of dielectric material. But, the relatively large amount of dielectric material in the connectors may increase the cost of manufacturing the connectors. Additionally, changes in temperature may result in thermal stresses causing cracks and other failures in the connectors due to mismatches between the coefficients of thermal expansion between the dielectric material, the contacts, and other components of the connectors.
Thus, a need exists for connectors that reduce electrical impedance characteristics of contacts in the connectors while avoiding or reducing the impact of some of the above problems in known connectors.